Some excellent tips. I'll add a couple more as my firearm photography skills slowly improve.
When shooting indoors near a window or large light source, don't overlook opportunities for "offset" or low-angle shots. These can offer drama, eye-catching looks and show off the lines of your subject firearm.
Backgrounds can be distracting and/or busy which detracts from your subject. On the other hand,
rjrivero's excellent work shows how to focus directly on the subject(s), but leaves little "flavor" to the scene. I photo'd this stainless steel gun on white & gray backgrounds but the look was too aniseptic for me. Adding the Mexican blanket caused the gun to jump out from the background more.
With stainless or nickel plated guns, taking an "offset" shot prevents light bounce-back if you use a flash. Here, fading natural light from the right was augmented by overhead light to compensate for the dark blued gun furthest from the main light source.
The use of an old wood table adds some flavor to the shot, while the accessories and ammo boxes is intended to convey something to the viewer. Hopefully it's a retired police officer's weapons.
